Faults with the new flagship device could be a major blow to the South Korean firm. Samsung was counting on the Galaxy Note 7 to maintain momentum against Apple's new iPhones — which are expected to be unveiled next week.

"This is some major buzz-kill for Samsung, especially given all of the hard-earned excitement that products like the Note 7 have been garnering lately," IDC analyst Bryan Ma said. "The timing of this couldn't have been worse."